Pull up following revision(s) (requested by reinoud in ticket #78):
sys/arch/usermode/usermode/pmap.c: revision 1.103
Move from pool(9) to kmem_zalloc(9) for L2 page tables. A pool with PAGE_SIZE
elements is accepted but seems to panic now and then claiming it can't find
the header info.
XXX should this be PR'd?

(riz)